AD 2021-10-23

This AD is effective July 6, 2021.

The Director of the Federal Register approved the incorporation by reference of a certain document listed in this AD as of July 6, 2021.

For service information identified in this final rule, contact Airbus Helicopters, 2701 N Forum Drive, Grand Prairie, TX 75052; telephone (972) 641-0000 or (800) 232-0323; fax (972) 641-3775; or at https://www.airbus.com/helicopters/services/technical-support.html. You may view the referenced service information at the FAA, Office of the Regional Counsel, Southwest Region, 10101 Hillwood Pkwy., Room 6N-321, Fort Worth, TX 76177. It is also available at https://www.regulations.gov by searching for and locating Docket No. FAA-2021-0126.

Matt Fuller, AD Program Manager, General Aviation & Rotorcraft Unit, Airworthiness Products Section, Operational Safety Branch, FAA, 10101 Hillwood Pkwy., Fort Worth, TX 76177; telephone (817) 222-5110; email matthew.fuller@faa.gov.

The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 by adding an AD that would apply to Airbus Helicopters Deutschland GmbH (AHD) Model MBB-BK 117 D-2 helicopters with a Ti-bolt part number (P/N) EN3740-060022F marked with manufacturer monogram “D” or with an illegible manufacturer monogram, installed on the aft connection of the tail rotor ball bearing control. The NPRM published in the Federal Register on March 3, 2021 (86 FR 12294). In the NPRM, the FAA proposed to require removing any affected Ti-bolt P/N EN3740-060022F from service. The NPRM also to prohibit installing an affected Ti-bolt on the aft connection of the ball bearing control of any helicopter. The NPRM was prompted by EASA AD 2019-0258, dated October 18, 2019 (EASA AD 2019-0258), issued by EASA, which is the Technical Agent for the Member States of the European Union, to correct an unsafe condition for Airbus Helicopters Deutschland GmbH (AHD), formerly Eurocopter Deutschland GmbH, Model MBB-BK117 D-2 helicopters. EASA advises of a report of a broken Ti-bolt. Subsequent investigation revealed that an improper heat treatment process was accomplished on a batch of Ti-bolts, which can lead to hydrogen embrittlement. Hydrogen embrittlement can make high-strength bolts susceptible to stress corrosion, pitting, and failure. EASA states that this condition, if not detected and corrected, could lead to failure of an affected Ti-bolt installed in a critical location, possibly resulting in reduced control of the helicopter.

Accordingly, EASA AD 2019-0258 requires a one-time inspection for Ti-bolt P/N EN3740-060022F marked with manufacturer monogram “D” or with an illegible manufacturer monogram installed on the aft connection of the tail rotor ball bearing control (ball bearing control) and, depending on findings, contacting AHD for corrective action. EASA AD 2019-0258 also prohibits the (re)installation of these Ti-bolts.

Comments

The FAA received no comments on the NPRM or on the determination of the costs.

These helicopters have been approved by EASA and are approved for operation in the United States. Pursuant to the FAA's bilateral agreement with the European Union, EASA has notified the FAA about the unsafe condition described in its AD. The FAA reviewed the relevant data and determined that air safety requires adopting this AD as proposed. Accordingly, the FAA is issuing this AD to address the unsafe condition on these helicopters.

The FAA reviewed Airbus Helicopters Alert Service Bulletin No. ASB MBB-BK117 D-2-00A-001, Revision 1, dated October 16, 2019, which specifies replacing each Ti-bolt P/N EN3740-060022F that is marked with manufacturer monogram “D” or if the manufacturer monogram cannot be identified with an airworthy Ti-bolt in both locations of the aft connection of ball bearing control and both high frequency (HF) antenna bracket locations.

This service information is reasonably available because the interested parties have access to it through their normal course of business or by the means identified in the ADDRESSES section.

EASA AD 2019-0258 applies to Model MBB-BK117 D-2 helicopters and requires inspecting for Ti-bolt P/N EN3740-060022F marked with manufacturer monogram “D” or with an illegible manufacturer monogram installed on the aft connection of the ball bearing control. This AD applies to Model MBB-BK 117 D-2 helicopters with a Ti-bolt P/N EN3740-060022F marked with manufacturer monogram “D” or with an illegible manufacturer monogram installed on the aft connection of the ball bearing control instead. EASA AD 2019-0258 requires contacting AHD for approved instructions if an affected Ti-bolt is found, whereas this AD requires removing an affected Ti-bolt from service instead.

The FAA estimates that this AD affects 29 helicopters of U.S. Registry. Labor rates are estimated at $85 per work-hour. Based on these numbers, the FAA estimates the following costs to comply with this AD.

Replacing a Ti-bolt takes about 2 work-hours and parts cost about $100 for an estimated cost of $270 per Ti-bolt.

Title 49 of the United States Code specifies the FAA's authority to issue rules on aviation safety. Subtitle I, section 106, describes the authority of the FAA Administrator. Subtitle VII: Aviation Programs, describes in more detail the scope of the Agency's authority.

The FAA is issuing this rulemaking under the authority described in Subtitle VII, Part A, Subpart III, Section 44701: General requirements. Under that section, Congress charges the FAA with promoting safe flight of civil aircraft in air commerce by prescribing regulations for practices, methods, and procedures the Administrator finds necessary for safety in air commerce. This regulation is within the scope of that authority because it addresses an unsafe condition that is likely to exist or develop on helicopters identified in this rulemaking action.

This AD will not have federalism implications under Executive Order 13132. This AD will not have a substantial direct effect on the States, on the relationship between the national government and the States, or on the distribution of power and responsibilities among the various levels of government.

For the reasons discussed above, I certify that this AD:

(1) Is not a “significant regulatory action” under Executive Order 12866,

(2) Will not affect intrastate aviation in Alaska, and

(3) Will not have a significant economic impact, positive or negative, on a substantial number of small entities under the criteria of the Regulatory Flexibility Act.

Accordingly, under the authority delegated to me by the Administrator, the FAA amends 14 CFR part 39 as follows:

1. The authority citation for part 39 continues to read as follows:

2. The FAA amends § 39.13 by adding the following new airworthiness directive: